Hello, I wasn't not sure how to solve this at all. If it's possible could you also show step by step. Thank You!

Question

35. Find the distance around the earth at the equator if the radius of Earth is 6,400 kilometers.

 a. 1.28 x 10⁸ km

 b. 20,096 km

 c. 40,192 km

 d. 80,384 km

I kept getting the answer as 20,106.

I did this formula to find the circumference, 3.14 x 6400= 20,106

Answer 1

Hello -

There are two key points here;

You equation for the circumference isn't quite right, Instead of pi * radius you want to use 2 * pi * radius

This will give you a number around 40,000

The second point is that it appears you used the exact value of pi (from a calculator) and the problem solution uses 3.14, this will lead to a slightly different answer.

2 * 3.14 * 6400 = 40192